Hard disk drive systems use a magnetic head to read and write magnetically encoded information on a magnetic disk. When the hard disk drive system is off, the magnetic head rests on the surface of the magnetic disk or is retracted from the surface of the medium to protect the medium. When the system is started, the hard disk is rotated about its central axis. The magnetic head remains in contact with the disk until the disk achieves a relative speed with respect to the head which enables the head to "fly" above the disk. Read and write operations are performed as the magnetic head flies above circular tracks on the hard disk.